Los Angeles daily herald., 1887-09-09

pOllut1ng SuDSOll wafer Is not IOunl
to be greater than from common
manuring, if the sewage distributed
per acre is not greater than what is
required for agricultural purposes
which condition may be readily
secured by the large area of lane
available for irrigation between Los
Angeles and the sea.
An inspection of both large anc
small sewage farms readily convinces
the observer that nuisance does not
exist anywhere, if their management
is under the care of fcompetent persons
even though the sewage is only one
half as much diluted as it is in this
city, which is most generally the C lse
in Europe. To avoid Objectionable
odors, such as are occasionally noticed
on the present farm a few miles south
of the city, the following precautions
are taken elsewhere with the desired
effect
| HOW IT is DONE.
Before the sewage is allowed to
spread over the ground the floating
matter is strained out and separately
disposed of by burning or otherwise.
1t will amount to but few bushels
per day, and, its fertilizing elements
having mostly been washed out, has
but an insignificant value. The sew
age will then hardly differ in appear
ance from that OF the water in the
common zanjas. The permanent
bitches or carriers distributing it are
made of concrete or of clay half
pipes, laid to even grades, and with a
smooth surface to prevent the reten-
ton and deposit of decomposable
matter, always caused by the rough
ness and Irregularities of an earth
trench. The temporary bitches OF
burrows are plowed up once or twice a
wear, and their location frequently
changed.
The sewage of the city is to be col
lected and removed by five different
classes of sewers:
Firstlv-The house drains, which
deliver it into the public system.
Secondly, the branch, and thirdly,
the main sewers, which collect it and
carry it down the natural depressions
of the territory. Fourthly, the inter
cepting sewers, which stop the sewage
from continuing in this natural course,
and bring it all to the southwest cor
ner of the city, which is obviously the
best point to collect it, and filthy, the
outfall sewer, which should begin at
this point and terminate at suitable
locality along the ocean beach.
THE MOST PRACTICABLE LINE.
Surveys made by Mr.. Eaton have
revealen the most practicable line,
considering both an irrigation and
ocean disposal, and serious difficulties
will not be encountered. The point
of discharge should be placed several
hundred feet from shore and the sew
age should be stored in reservoirs and
allowed to flow out only during the
first hours of outgoing tide.
The outfall sewer, will be about 1l.5
miles long. Its form should be egg
shaped rather than circular, because
its efficiency is thereby greatly in
creased for a number OF years, when
the flow will be comparatively slight.
Its dimentions are four feet by five
feet and six inches. which allows am
pie :for sthe sewage of over 100000
persons.
If the sewage is diverted for irriga-
ton, the section to the ocean can serve
to great advantage as relief sewer
during the rainy seasoa, or at other
times when the crops do not need all
the water which it carries.
In order to deliver the sewage OF
the entire city at the southwest corner
the territory is best divided, as indi-
Gated by the topography and shown by
the accompanying map, into three in
dependent main districts, the western,
central and southern. The sewage
from each one respectively is collected
by intersecting sewers leading to the
outfall. A careful study has been
made of their alignment in order to
make them as direct as practicable
and combine economy and efficiency.
The broken country near the western
boundary of the city renders a loca-
ton somewhat difficult, and for the
sake of avoiding considerable tunnel
ing it was for some distance carried
outside the city. About SIS acres in
the southeastern corner are too low to
be directly drained by the intercept
ing sewer of the southern district, and
the sewage from this area will have to
be collected by a special system OF
low-level sewers and discharged into
the general system by pumping
THE THREE MAIN DISTRICTS.
| The three main districts are divided
into number of smaller ones, de
termined by the natural divides, and
the seweage from each one is deliv.
cred into the inceptor, either directly
by branch sewer when the area is
small, or it is first collected into a
main sewer when the area is sutfi.
GENTLY large.
The lines of the main sewers with
their respective districts and also the
intercepting sewers are shown on the
accompanying map.
The determination OF the amount OF
liquid to be removed by the sewers,
which governs their size, is matter
of considerable importance. In most
large cities it is customary, and prop
erly so, for economical reasons, to use
pipes for the double purpose of sew
age and rainfall removal. In Los
Angeles the advantages for doing this
do not exist. The fact that for many
months in the year no rain falls, and
that when it does rain the storm water
can be more economically disposed OF
otherwise than through the out-fall
sewer, renders it inadvisable to ex-
pend the large sum of money, amount
ing to several millions of dollars, re-
quired to receive it into the sewage
system. And further, should the out
fall at present be confined to the pro-
posed irrigation tract, the large guam
tity OF rainwater discharged upon the
same, together with the sewage,
would be very difficult, if not imprac-
ticable, to deal with.
Therefore, it is best to adopt what is
known as the separate system, used in
Europe and America for many years
under similar conditions, confning
the sewers to the waste-water from